Bug 1891740 - Re-enable test_ext_manifest_incognito.js in condprof r=rpl

Differential Revision: https://phabricator.services.mozilla.com/D207569

toolkit/components/extensions/test/xpcshell/xpcshell.toml

@@ -75,7 +75,6 @@ skip-if = ["os == 'android'"] # Not shipped on Android
 ["test_ext_manifest_content_security_policy.js"]
 
 ["test_ext_manifest_incognito.js"]
-skip-if = ["condprof"] # remove in a few days - see bug 1891740
 
 ["test_ext_manifest_minimum_chrome_version.js"]